Yellow dye.



UNITED STATES Patented. June 6, 1905.

PATENT OEEIcE.

Hueo WITTER, OF ELBERFELD, GERMANY, AssIeNoR TO FARBENFA- BRIKEN OF ELBERFELD 00., OF NEW YORK, N. Y., A CORPORA- TION OF NEW ORK.

YELLOW DYE.

SPECIFICATION forming part of Letters Patent No. 791,525, dated June 6, 1905.

" Application filed March 13, 1905. Serial No. 249.814-

To all whom it may concern.-

Be it known that I, HUGO WITTER, doctor of philosophy, chemist, (assignor to the FAR- BENFABRIKEN or ELBEREELD COMPANY, of New York,) residing at Elberfeld, Germany, have invented a new and useful Improvement in Yellow Coloring-Matter; and I hereby de- 7 portion of alpha-methylindol (methylketol) the tetrazotized derivatives of benzidinor tolidin-meta-disulfonic acid, having the following general formula:

in which formula X means hydrogen atoms which can be replaced by the methylic group.

The new coloring-matters are, in the shape of their alkaline salts, brownish powders soluble in water and in concentrated sulfuric acid with a yellow color and yielding upon reduction with stannous chlorid and hydrochloric acid the diamido-diaryldisulfonic acids of the above-given general formula amidomethylphenylpyrazolon and amido-alphamethylindo]. They dye wool from acid-baths yellow shades fast to milling.

In carrying out my invention practically I can proceed as follows,(the parts being by weight:) Three hundred and forty-four parts of benzidin-meta-disulfonic acid are diazotized in the usual manner with the aid of one hundred and thirty-eight parts of sodium nitrite and hydrochloric acid, and to the resulting tetrazo compound a solution of .one hundred and forty parts of alpha-methylindol in one thousand parts of hydrochloric acid (20 Baum) is added. After the addition of an excess of sodium acetate it is stirred until the verized, a brownish powder soluble in water and in concentrated sulfuricacid with a yellow color. Upon treatment with stannous chlorid and hydrochloric acid benzidin-metadisulfonic acid, amidomethylphenylpyrazolon and amido-alpha-methylindol is obtained. It dyes wool from acid-baths yellow shades.

The process proceeds in an analogous manner on replacing the benzidin-meta-disulfonic acid by the tolidin-meta-disulfonic acid.

Having described my invention and in what manner the same is to be performed, what I claim as new, and desire to secure by Letters Patent, is

1. The herein-described new tetrazo dyestuffs obtainable by the combination of the tetrazo compounds of the para-diamin-disulfonic acids having the above-given general formula with one molecular proportion of alpha-methylindol and one molecular proportion of phenylmethylpyrazolon, which dyestuffs are in the shape of their alkaline salts brownish powders soluble in water and in concentrated sulfuric acid with a yellow color; yielding on reduction with stannous chloriol and hydrochloric acid the diamidodiaryldisulfonic acids of the above-given formula, amidomethylphenylpyrazolon and amidoalphamethylindol; dyeing wool yellow shades fast to milling, substantially as hereinbefore described.

2. The herein-described new tetrazo dyestuff obtainable by the combination of the tetrazo compound of benzidin-meta-disulfonic acid with one molecular proportion of phenylmethylpyrazolon and of alpha-methylindol; which dyestufi' is in the shape of its sodium salt a brownish powder soluble in water and in concentrated sulfuric acid with a yellow color, yielding on suitable treatment with stannous chlorid and hydrochloric acid benzidin-metadisulfonic acid, amidomethylphenylpyrazolon and amidoalpha-methylindol; and dyeing Wool from acid-baths yellow shades, substantially as hereinbefore dc- I scribed.

In testimony whereof I have signed my name in the presence of two subscribing witnesses.

HUGO WITTER.

Witnesses:

OTTO KoNIG, J. A. RUTHERSI-IAUS. 

